The present invention relates to a disk transfer device and, more particularly, to a disk transfer device which grips the outer edge of a disk during the disk transfer.
Japanese patent application SN 7-72281 (Japanese Laid-Open Publication Number 8-241552), discloses a disk transfer device which transfers a disk by gripping its outer edge. The disk transfer device described in this publication comprises: a driven disk guide which guides a first edge of a disk in the disk transfer direction and which has an internal driven belt which drives this disk edge; a fixed disk guide which guides a second disk edge in the disk transfer direction and which is equipped with a friction sheet which prevents slippage between it and this disk edge; and springs which draw the disk guides closer together. With this disk transfer device, a disk is gripped between the disk guides and is transferred to the playback position by driving one edge of the disk with a drive belt.
In the disk transfer device described above, the spring force of the springs connecting the disk guides must be strong, if the disk is to be securely gripped during the transfer. Such a grip is necessary to insure positive disk transfer regardless of external vibrations or the vertical orientation of the device. However, because disk insertion necessitates pushing apart the disk guides, if the spring force is too strong, there is a large amount of resistance to disk insertion. This problem is particularly acute in a disk transfer device which is capable of transferring both large disks of 120 mm diameter and small size disks (called single CDs) of 80 mm diameter. To make the transfer of small size disks possible, the initial spacing of the disk guides must be made narrower than the diameter of these disks. As a result, the spacing is too narrow for insertion of a large size disk, and an extremely large amount of insertion force is required. On the other hand, if the spring force is set for a large size disk, the disk gripping force becomes extremely weak when transferring a small size disk because the spring is insufficiently stretched. In such circumstances, the disk may be insecurely gripped and transfer may be unreliable.